Coil mounting



G. L, BEERS con, MOUNTING Filed Jan 2' 1926 :WIIINUNN Feb. 19, 1929'mvENTOR fylm wlTNEsSESI d f l ATTORNEY G. L. BEERS con. MOUNTING Feb.'19, 1929.

Filed Jan. 2, 1926 2 sheets-sheen E RB O. T/ Ne wi my E 6 wlTNEssEs:

AT'ONY Patented Feb. 19, 1929.

UNITED STATES4 PATENT OFFICE.

GEORGE Il. BERRE, l' WILKINSBUBG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSEELEUIBIC MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

COIL MOUNTING.

Application led January 2, 1926'. Serial No. 78,792.

My invention relates to the mounting of inductances such asl are used inradio receiving or transmitting systems and has particular reference tothe mounting of such coils when they are to be used in small places.

The principal object of my invention is to devise methods of and meansfor, mounting a plurality of inductances in close relation whereby theinductive coupling therebetween will be held at a minimum.

A further object of my invention is to provide means whereby therelative positions of such inductances may be changed and,

A still further object of my invention is f to provide an inductancemounting which will be easy to assemble and which will hold theinductance firmly in position.

It has been found, when building a radio receiving or transmitting set,that very often undesired couplings exist between the componentinductances, which is an obvious disadvantage. It has also been foundnecessary in the construction of portable receiving sets to place coilsbelonging to different circuits in rather close relation. This, ofcourse, re-

sults in undesired inductive coupling between the coils.

It is old and well known that coils may be connected astatically so thatthe outside field is reduced to a minimum. With these conditions inmind, I have designed a mounting whereby an astatic coil in, forexample, the plate circuit of one tube ma be placed rather close to acoil which might be in the grid circuit of the same tube or in the gridor plate circuit of another tube and, at the same time, I am enabled toavoid undesired cou ling between these two sets of inductance. '1lbaccomplish this result I so locate an astatie inductance composed of twosections, with reference to a single inductance, that the inductiveeffect of each half of the astatic inductance on the. single inductanceis neutralized.

I have also devised a method of mounting the various inductancesinvolved in this system in such manner that they will at all times befirml held in position, will not be subject to de ormation, and may beeasily assembled. I accomplish these results by em loying inductances ofthe spider-web or baset-wound type and attaching them flat against aninsulating support, using as an attaching means a continuous strand ofcord or analogous material.

For a more complete understanding of my 1nven tion, reference is made tothe accompanying drawings forming a part of this specification in which,

Figure 1 is a plan view of a preferred form of my astatic system;

Fig. 2 is a cross section of the same on the line II-II;

Fig. 3 is a detail View of the astatic inductance assembly;

y Fig. 4 is a back view of the assembly showing the manner in which theinductances are attached to the support.

In Fig. 1, inductances 1 and 2 are positioned astatically. In otherwords these inductances are both wound in the same direction and theouter ends are connected together at 3. fl'hese inductances are firmlysecured to an insulating support 4 by means of a iiliform element 5which is more clearly shown in Figs. 3 and 4. The second inductance 6 ispositioned below the first inductance assembly as shown in Fig. 2 and isspaced therefrom by means of a spacer 7.

The second inductance 6 is also secured to a support 8 by a cord orother element analogous to that by which coils 1 and 2 arc held on thesupport 4. The support 8 is provided with a. central opening 9 throughwhich passes the bolt 10 carrying the spacer 7. The aperture 9 is madeconsiderably larger than necessary to pass the bolt l0 and on eitherside thereof are placed washers 11, which as sembly permits a relativeadjustment of supports 4 and 8.

Referring to Fig. 3, the support 4, of insulating material, 1s providedwith a plurali t of holes 12 in addition to the central hole.

hrough these holes is passed the cord 5,

which secures the inductances firmly against the insulating support.

In Fig. 4, which 1s a back view of the support 4, is more clearlybrought out the manner in which a single continuous cord is used to holdthe two inductances against the suport. P It will be noted that when acurrent in any given direction passes throu h inductance 1, a magneticfield is set up w iich is opposite in sense to that set up by inductance2, which is connected astatically to inductance 1. The voltage inductedin inductance 6 by inductance 1 is, therefore, opposite in direction tothat induced by inductance 2. To secure a perfect balance, it is usuallynecessary to shift the position of inductances 1 and 2 along an axis ofinductance 6 or perhaps along a chord of inductance 6. This adjustmentis provided for by the assembly shown in Fig. 2 in which, by looseningthe nut 13 the pressure on washers 11 is released and the upper support4 is permitted to be adjusted to the desired position.`

Referring more particularly to the manner of securing the coils on thesupport, in Fig. 3 it will be noted that the continuous cord does notpass over the inductance but is threaded through the space left by thewinding forni peg, enabling this cord to be drawn as tightly as desired,and knotted as shown in Fig. 4.

The entire assembly may be dipped, if dedcsired, into an insulating andmoisture resistantvaruish or the like, or the coils may, of coui'se, beso treated before mounting. It is obvious that in lieu of the singlecontinuous cord 5 a plurality of separate lengths of cord may be usedwithout departing from the spirit of my invention. It is also obviousthat the holes 12 in the insulating plate 4 may be replaced byprotuberances around which the cord may be placed.

By this method of :istatically positioning three coils, I am enabled tobuild a receiving set or other radio apparatus having much smallerphysical dimensions than when the usual type of inductances areemployed. I am also enabled by my invention to quickly position theseinductances on their mountings, and to obtain at much less expense thanusual, an assembly which is quite durable, compact, and readilyreplaceable as a unit.

Although I have illustrated and described a single specific embodimentof my invention, certain obvious changes falling within the range ofwel] known equivalents will suggest themselves to those skilled in theart. Accordingly, I do not desire to be limited eX- cept as required bythe prior art and as indicated in the accompanying claims.

I claim as my invention:

l. An inductor assembly for radio-receiving apparatus, comprisin 'aplurality of astatically-connected spira ly-Wound coils, a secondspirally-wound coil, means for supporting said astatically-connectedcoils in a plane substantially (parallel to the plane of said secondcoil, an means pern'iitting limited lateral motion of said coils intheir respective planes, whereby their mutual inductance may be reducedto the lowest value consistent with the vertical distance between thesaid planes.

2. In combination, two astatically-connected inductors of the spidea-webtype lying substantially in the saine plane with their perimetersclosely adjacent, a planar insulating support, filiform means forholding said inductors against said support, a single inductor of thespider-web type having a diameter commensurate with the combineddiameters of the two first vmentioned coils, and means for positioningthe second coil in a plane substantially parallel to the plane in whichlie the first mentioned coils and adj acent thereto.

3. In combination, two astatically-connected inductors of the spider-webtype, means for supporting said coils in a single plane with theirperimeters adjacent to each other, a single inductor of the spider-webtype, and adj ustable means for movably positioning the second inductorin a plane parallel to the plane in which lie the first mentionedinductors and adjacent thereto, whereby the coupling between said firstmentioned coils and the single coil may be adjusted to minimum value.

In testimony whereof, I have hereunto subscribed my name this first dayof December,

GEORGE L. BEERS.

